可穿戴式汗液传感器

News &Highlights

Wearable Elizabeth K.Senior Technology Writer

sors could take the place of invasive blood draws.They might ana-lyze creatinine,to assess kidney function,or cortisol,to track the stress response.Wearable sweat sensing devices could potentially allow continuous biomonitoring,eliminating the need for bulky equipment,repeat visits to labs,or hospital stays.

Recently,an international team led by John A.Rogers,the direc-tor of the Center for Bio-Integrated Electronics at Northwestern University,unveiled what may be the most sophisticated proto-type sweat sensor developed to date (Fig.1).The device not only monitors lactate,glucose,chloride,and pH,but also sweat rate and loss [1].The ability to measure these last two parameters is particularly novel,and crucial for understanding their effects on the composition of sweat samples.

The Rogers group’s device features a flexible elastomeric system of microfluidic channels,valves,and chambers that are removable and can be swapped out for new ones,enabling reuse.The natural action of sweat glands pumps sweat through holes in the bottom of the device into the channels and analysis chambers,each contain-ing a sensor for a different substance.While enzymes in biofuel cell-based,electrochemical sensors catalyze reactions that increase with concentration to assess lactate and glucose levels,the device measures chloride and pH colorimetrically by comparison to color calibration markings.The device transmits and receives data to and

from the same cell phone that powers it via near-field communica-tion (NFC)ing this external power source makes the patch up to 20times lighter and four times smaller than devices that rely on batteries.

Other labs take different approaches.At the California Institute of Technology (Caltech),medical engineering assistant professor Wei Gao and his team believe sweat can be used for many compli-cated analyses involving substances such as heavy metals,drug molecules,and hormones and other proteins.Before moving to Cal-tech,Gao was a postdoctoral fellow in the laboratory of engineer-ing professor Ali Javey at University of California,Berkeley (UC Berkeley),where he helped develop a wearable sensor for caffeine as a model for detecting methylxanthine drugs [2].Unlike the devices powered via NFC,the Gao lab’s prototypes use tiny batter-ies.For some continuous monitoring applications,Gao said,staying close to a cell phone may not be practical.

Yet another team,headed by Hong Liu at Southeast University in Nanjing,recently designed a wearable glucose sweat sensor that,unlike the Rogers’device,does not rely on enzymes [3].These biomolecular components present a number of issues for sensor development.For example,enzymes are sensitive to pH,tempera-ture,and ionic strength;they can degrade over time;and the

1.Developed by an international team of collaborators,this prototype,battery-sweat sensor can monitor lactate,glucose,chloride,pH,and sweat rate and loss.sensor wirelessly transmits and receives data to and from the same cell phone that powers it by via near-field communication (NFC)technology.Credit:John Rogers,Northwestern University.